The Los Angeles Police Department has launched an internal investigation after one of its officers was caught on camera apparently kicking a cyclist during a protest against oil giant BP on Friday.

According to the Los Angeles Times, the incident took place on Hollywood Boulevard during a "Critical Mass" cycling event. Critical Masses -- which involve cyclists riding through the streets to call for cyclists' rights -- typically take place on the last Friday of every month. This particular event targeted BP for its role in the Gulf oil spill.

Video of the incident, which was posted to YouTube, shows what appears to be a police officer stepping out and kicking at a passing bicycle.

"Whoa, what the f*** was that for?" the unidentified cameraman can be heard saying. Moments later, the video shows two officers converge on the cameraman and take him down to the ground.

"Get up," one officer can be heard saying, as another says "Stay down."

Story continues below..."What did I do?" the cameraman can be heard saying.

According to the LAist, between 200 and 1,000 cyclists took part in the protest, which made its way from Los Angeles into Hollywood. The Weho Daily blog reports that "interaction with the LAPD took a turn for the worse in Hollywood ... where a few riders were taken down by officers."

"The vast majority of the police along the way were helpful and accommodating," a witness told Weho Daily. "But for whatever reason the police in Hollywood were extremely aggressive and were harassing riders for no reason other than to get their kicks (I presume)."

The president of the Los Angeles Police Protective League said in a statement quoted by the Times that people shouldn't "rush to judgment" about the video.

"It is always important to remember that home video, shot from a distance, from one angle and in the dark, and not at the beginning of the incident seldom tells the whole story," Paul M. Weber said.

The following video was filmed on Friday, May 28, 2010 and uploaded to YouTube by user manueldogg.